A strategy doesn't have to be planned to be executed.

A random mutation that causes the virus to be more mild would cause people to rationally take fewer precautions against it. Then it gets to spread more, which is evolutionarily advantageous to the virus, but it doesn't kill as many people, which is advantageous to humans.

Note that there are a ton of viruses people get infected by on a regular basis that don't even have symptoms. Those viruses "spread like the plague" but because they're not the plague, nobody cares.

It probably makes no sense to talk of a virus having a strategy. I don’t agree with all of his stuff but the point of Daniel Dennett’s “intentional stance” is basically that attributing mental states to things is just a pragmatic matter. If it helps us understand virus behavior better to treat them as if they have strategies (which implies mentation), then we should do it. I don’t see how it would help at all here, though.

The simplest version of survival of the fittest, continued existence. Entropy preserving entropy, it's more of an emergent property of reality than a strategy.

Random mutations cause random changes to "strategy", and viruses with "strategies" that cause them to spread faster become more common

the random mutation concept is close to but not exactly the situation. there is a low frequency event that results in mix and match of large regions of sequence. This is very different from error prone replication error, or point mutation.

this occurs when a host is coinfected with two or more viral strands of differing origin. most often virus of close familial lineage do this, but that isnt exclusive.

the mechanism is molecular promiscuity during replication, there is a jump from one strand to another in proximity, thus recombining.

cocirculation is required for this to occur, high frequency of co infection is required for recombinant mutants to occur with predictive certainty.

like the gatekeeper and the keymaster, we should avoid allowing delta, and omicron to contact each other, and surveil the sequences closely.

It's similar to Dawkins' "selfish gene" analogy.

It’s “just” Darwin’s theory, ie “survival of the fittest” at work. The virus isn’t conscious and isn’t choosing a strategy.